Portable grinding tool



May 27, 1930. E, A HALL PORTABLE GRINDING TOOL Filed July 20, 1927Patented May 27, 1930 UNITED srArEs P TEN-r OFFICE ERNEST A. HALL, OFTOLEDO, OHIO, ASSIGNOR TO THE HALL MANUFACTURING 60.,

' OF TOLEDO, OHIO, A. CORPORATION OF OHIO PORTABLE GRIN DING TOOLApplication filed July 20,

p This invention relates to grinding tools and particularly to those ofa portable nature adapted for grinding the valve seats of internalcombustion engines.

a An object of the invention is the provision of a tool of the characterdescribed, which s rapid, accurate and eficient in its work and is animprovement in certain respects on the tool heretofore invented by meand covered to by pay Patent No. 1,636,560, dated July 19,

The invention is fully described in the following specification and oneembodiment thereof illustrated in the accompanying drawlt ings, inWhich,-

Figure l is a central longitudinal section of a tool embodying theinvention mounted in operative relation to the valve seat of an enginecylinder, Figs, 2 and are reduced at sections, respectively, on the hnes2-2 and 3-3 in Fig. l, with parts broken away, and l ig. d is asectional view on the line t-d lll fieferrin g to the drawin s, ldesignates an $55 engine cylinder with the ead cap thereof removed torender the valve seats accessible for grinding, one of which seats isshown and designated 2. Below and coaxial with the valve seat isprovided the customary valve to stem hearing, which, in the presentinstance,

is formed by the bushing 8. I

The tool embodying the invention includes a support or pilot member 4,which comprises a stem adapted to be fitted at its lower end down intothe valve stem bearin 3, whereby it is supported in true centererelation to the valve seat 2, the upper end of the stem being rejected adistance above the valve seat... order to accurately center the stem lwith respect to the valve seat and to firmly hold it in such position,the stem has a tapered ortion 5 which has centering ooaction with t eupper end of the bearing 3 and has a nut 6 threaded on its lower end andprovided with a tapered extension 7 adapted to fit into the lower end ofthe bearing to have centering coaction therewith. The tool proper,separate from the support or pilot 4 includes in its present embodiment,inner and outer shafts 8 and 9, respectively,

1927. Serial 1T0. 207,168.

the outer ,shaft being carried by and mounted to rotate in a casing orholder 10 and the inner shaft being mounted in the outer shaft for freeturning movements relative thereto. The shafts project at their lowerends below the casing 10 and the outer shaft 9 carries a grinding wheel11 at its lower end having a grinding face suited, for grinding coactionwith the valve seat 2. This wheel, however, is not intended to havesimultaneous coaction with the valve seat entirely around thecircumference thereof, as in my former Patent No. 1,636,560, but isodset with respect to the center of the valve seat so that only one sideportion of the grinding wheel has coaction with the annular seat orsurface to be ground. This lateral ofisetting of the grinding mem ber llwith respect to the valve seat is accomplished by providing the lowerend of the inner shaft 8 with an eccentric bore 12 into which the upperendof the stem l fits in a manner to permit the shaft or sleeve 8 tohave both rotary and axial movements thereon. lit is apparent that aturning of the inner shaft 8 on the stem 4 will edect an annularshifting of "the point of bearing or grinding coaction of the grindingmember 11 with the valve seat, and that such coaction will be carriedentirely around the valve seat by a complete turning movement of saidshaft.

For efiective work, the shaft 8 should be slowly rotated while the shaft9 carrying the grin-ding member 11 should be more rapidly rotated. Forthis purpose, power transmission means is carried in the upper enlargedportion of the casing 10 and communicates rotation at the requisitespeed from a common source to the two shafts. In the present instancethis mechanism comprises a maindrive s aft 13 journalled in the upperenlargement of the casing 10 transversely thereof at one side of theupper end portion of the shaft 9 and has one end connect-ed, pref erablyby a flexible shaft 14, to a suitable power source. The shaft 13 is alsoconnected through a train of speed reduction gears 16 to a large gear 17on the upper end of the inner shaft 8, which shaft end projects abovethe upper end of the outer shaft 9 for such purpose. It is thus apparentthat both shafts a bar 11 about its axis and the other 8 and 9 arerotated at relatively different speeds, one for the purpose of impartinga rapid grinding rotation to the grindin memor the purpose of impartinga slow revoluble shiftmg movement to the seat contacting side of thegrinding member to cause it to repeatedly the seat during the grindingoperation, than is possible by having the grindin member arrangedconcentric to the seat to e ground and simultaneously contacting withsuch seat entirely around its axis, as is the case with the tooldescribed in my said former Patent No. 1,636,560,

' The tool with its abrading member is supported with respect to thevalve seat, and t e grinding pressure of the abrading memberthereagainst is gauged in the same general manner as described in saidformer patent, namely, b projecting a gauge rod 18 down through t e uper end the casing 10 and axially throug the shaft 8 into engagement atits lower end with the upper end of the stem 4, the upper end of the rod18 being threaded in the upper end portion of the easing to facilitatelongitudinal adjustment of the rod. A knurled head 19 is provided on theouter end of the rod 18 to facilitate turning. The rod 18 is locked inadjusted position by a set screw 20.

- The outer shaft 9 is rotatably centered within the casing 10 by upperand lower bearing sets 21 and 22, respectively, which are mounted in thereduced neck or lower end portion of the casing 10 and are spaced by asleeve 23, which, in the present instance, is fitted on the shaft 9 andsecured thereto by a set screw 24. The lower bearing 22 rests on aninturned flange 25 at the lower end of the casing and also engages ashoulder formed at the inner end of an enlarged portion of the shaft 9which rojects through the openings formed by the ange 25 and a stuffingbox carried thereby. The upper bearing 21 is held to its seat on theupper end of the sleeve 23 by a collar 26 threaded in the upper end ofthe neck ortion of the casing 10, and this in turn is loclfed inadjusted position by a lock nut or collar 27. A sleeve 28 encircles theshaft 9 within the collars 26 and 27, having its lower end thrustagainst the bearing 21 and its upper end thrust against the gear 15 onthe shaft 9. a

The inner shaft 8 is supported within the shaft 9 by the shouldering ofthe lower hub end of the gear 17 against the upper end of the shaft 9.The portion of the casing 10 through which the rod 18 is threadedcomwhen the cap has been removed.

It is apparent that upon removal of the cap 29- the shaft 8 and its car17 may be withdrawn upward throug the casing opening and that after thegrinding member 11 has been removed from the shaft 9 and'the col lars 26and 27 removed from threaded engagement with the casing 10, said outershaft, the bearings 21 and 22 and sleeves 23 and 28, together with thegear 15 on said shaft, may be removed as a unit from the casing.

I wish it understood that my invention is not limited to any specificconstruction, arrangement or form 0 theparts, as it is capable ofnumerous modifications and changes without departing from thespirit ofthe claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is 1. In a tool of the class described, a guidefixed with respect to the work, a shaft rotatable on said guide ineccentric relation thereto, a second shaft rotatable on said firstshaft, a rotary abrasive member carried by the second shaft without saidguide, and positively driven intergeared means for imparting rotation tosaid first shaft about said guide and to the second shaft about thefirst shaft.

2, In a tool of the class described, a guide fixed with respect to thework, a shaft rotatable on said guide in eccentric relation thereto andlongitudinally movable thereon, a second shaft rotatable on the firstshaft, a rotary abrading member carried by the second shaft without saidguide, and means for imparting rotation to each of said shafts atrelatively difierent speeds having a fixed ratio to each other.

3. In a tool of the class described, a guide fixed with respect to the,work, a shaft rotatable on said guide in eccentric relation thereto andlongitudinally movable thereon, a second shaft rotatable on the firstshaft and having a rotary work abrading part without said guide,intergeared means for imparting rotation to. each of said shafts, andmeans adjustably cooperating with said guide to move the shaftslongitudinally of the guide.

4:. In a tool of the class described, inner and outer shafts axiallymovable together and mounted one on the other for free relative rotarymovements, an abrading element carried by the outer shaft, a pilotengageable with the inner shaft, means for detachably securing the pilotin position to hold the inner shaft and the other shaft with their axesin laterally ofiset relation to the center of the work, and intergearedmeans for imparting rotation to each of said shafts with the rotation ofone different from that of the other, and

means connecting the pilot and outer shaft through the inner shaft andoperable in operation with the pilot during .a running of the outershaft to axially adjust the shafts and abrading element toward or awayfrom thework.

5. In a tool of the class described, a hollow casing having an openingat one end thereof, a removable closure member for said opening, innerand outer shafts mounted one on the other within the casing for freerelative rotary movements and projecting from the opposite end of thecasing to said opening, an abrading element carried by the outer shaftwithout the casing, a pilot engageable with the inner shaft, means fordetachably securing the pilot in position to hold the inner shaft andthe other shaft with their axes in laterally offset relation to thecenter of the work, intergeared'means for imparting rotation to eachofsaid shafts withthe' rotation offone different from that of the other,and means carried by said closure, member and adapted to cooperate withthe pilot during a running of the shafts to effect an axial adj ustmentof the abrading element toward and away from the work.

6. In a tool of the class described, a casing, two shafts mounted onewithin the other in the casing for rotary movement relative to eachother and to the casing, the outer shaft projecting beyond the casingand having a rotary work abrading member, aguide adapted to be fixedwith respect to the work and v having engagement with the inner shaft tocause its axis and that of the outer shaft to have a relative movementabout a predeter- 'mined center when the inner shaft is rotated, andmeans mounted in the casing for driving 40 said shafts at differentspeeds having a definite predetermined ratio. In testimony whereof Ihave hereunto signed my name to this specification. ERNEST A. HALL.

